Depressive rumination is defined as repetitive thinking about the causes, symptoms, and meaning of one's depressed mood. Rumination is associated with serious negative consequences, such as more severe, longer- lasting, and more numerous episodes of major depression. To understand why some individuals engage in such maladaptive thinking, previous research has attempted to elucidate cognitive mechanisms that may underlie rumination. Findings from this research suggest that inhibitory deficits make it difficult for ruminators to remove from working memory (WM) information that is no longer relevant and to exert cognitive control to keep irrelevant information from entering WM. Although this research has been successful in identifying cognitive aspects of rumination, little work has been conducted elucidating the neural mechanisms that underlie rumination. Identifying the neural underpinnings of rumination has the potential to increase our understanding of the mechanisms that drive this process. In this context, the overarching goal of the proposed research plan is to elucidate the neural mechanisms of depressive rumination. One aim of this research is to use fMRI to identify brain regions associated with ongoing ruminations and to identify the neural mechanisms by which ongoing ruminations impair individuals' ability to control their attention. A second aim of this research is to use fMRI and behavioral studies to examine the neural mechanisms that underlie the cognitive deficits that characterize individuals with a high tendency to ruminate. These studies will help to elucidate the neural mechanisms that may make it difficult for ruminators to control the contents of their WM. We will distinguish neural mechanisms that may precede and underlie a tendency to ruminate from mechanisms that may be a consequence of depressive rumination.